Searching Ovid: Embase
Searching with Subject Headings
Subject Headings
Subject headings are words or short phrases that are added to the records of every item in the database. Subject headings use a ‘controlled language’, meaning there is only one word or phrase used to describe a specific concept.
More On Controlled Language
In theory, this means that every reference discussing rehabilitation, for example, will have a subject heading related to rehabilitation. Searching using subject headings will retrieve references on a topic regardless of the wording used by individual authors. You can often type in the brand names of drugs and Embase will find the corresponding generic drug name.
Explode and Focus Functions
Using the Explode and/or Focus functions with your subject headings may give your search results more relevance.
We recommend searching for each concept of your search one at a time. This allows greater flexibility later on when combining your search lines.
If you can’t find a subject heading to match your search term(s) using the instructions below, try again using some synonyms.
If that does not work, search by keyword instead.
- In Advanced Search, leave the Map Term to Subject Heading box ticked (it will be ticked by default).
Enter your search term and click the Search button.
- This will take you to a display of suggested subject headings that match your search term. Find the heading that best matches the concept, and click on it to reveal broader and narrower subject headings. This may help you to find similar headings, and will help you to decide whether or not to explode and/or focus.
You can click the Scope icon to find out the definition of a heading.
If there is more than one suitable heading, you can select them all at once, but we recommend taking one heading at a time and repeating the process to add extra subject headings.
For your chosen heading(s), you have the option to Explode the heading(s), Focus the heading(s), or both.
- Explode includes your selected subject heading and all of the Narrower Terms below the heading. This will increase the number of results by including references related to relevant sub-topics.
- Focus retrieves references that have this subject heading as their main topic. This will find fewer results, but with higher relevance.
- Both – you can select both options to include a wider range of headings (explode), but only when they are the main topic of the article (focus).
- Tick the relevant boxes as appropriate:
- Once you have made your selections, scroll back to the top of the page and click the Continue button:
Depending on your selections, you may be taken to a list of Subheadings.
We recommend clicking Continue here without selecting any of the subheadings . This will automatically include all references that have your chosen subject heading(s).
Choosing any subheading rules out any references that have no subheadings at all, as well as potentially relevant references with different subheadings. For this reason, we generally advise not to use them.
- Clicking Continue will take you back to the search screen, where your search line will be listed in the Search History:
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If your search reaches 5 lines or more, you can click Expand on the right to see the entire search history:
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